William Harvey's theory on Circulation of Blood deals elaborately in this slide. Every one must know the method of blood circulation

1. Dr.V.Natchathira Selvakumari
Assistant Professor of History
V.V.Vanniaperumal college for Women
Virudhunagar

2.  William Harvey, (born April 1,
1578, Folkestone, Kent, England—died June
3, 1657, London), English physician who was
the first to recognize the full circulation of
the blood in the human body and to provide
experiments and arguments to support this
idea.

4.  Harvey had seven brothers and two sisters, and
his father, Thomas Harvey, was a farmer and
landowner. Harvey attended the King’s School
in Canterbury, Kent, from 1588 to 1593 and went
on to study arts and medicine at Gonville and
Caius College, Cambridge, from 1593 to 1599.
He continued his studies at the University of
Padua, the leading European medical school at
the time. He became a student of Italian
anatomist and surgeon Hieronymous Fabricius,
who had a considerable influence on Harvey. It is
also likely that Harvey was taught by Italian
philosopher Cesare Cremonini, a prominent
follower of Aristotle.

5.  Harvey earned his doctorate from Padua on April 25, 1602, and
then returned to England to work as a doctor. In 1604 he
married Elizabeth Browne, the daughter of Launcelot Browne, a
London physician, who served as physician to James I, the king
of England and Scotland. Harvey and his wife appear to have
been happy together, and Harvey referred to her as “my dear
deceased loving wife” in his will. However, they did not have any
children. Harvey was a fellow of the Royal College of
Physicians of London from 1607 and was active in this society for
the remainder of his life. In 1615 he was appointed Lumleian
lecturer in surgery at the Royal College, a post he held until 1656
(the Lumleian lecture series was named after Lord John Lumley).
In 1609 he was appointed physician at St. Bartholomew’s
Hospital, a post he held until 1643, when the parliamentary
authorities in London had him replaced, Harvey being a staunch
supporter of the monarchy.


6.  Harvey was appointed physician to James I in 1618
and continued as physician to Charles I upon
Charles’s accession to the throne in 1625. Harvey
built a considerable practice in this period, tending to
many important men, including author and
philosopher Sir Francis Bacon. In 1625 Harvey led the
group of doctors attending James during his last
illness and was an important witness in the trial
of George Villiers, duke of Buckingham, who was
accused of poisoning the king. Harvey was rewarded
by Charles I for his care of James. Charles and Harvey
seem to have enjoyed an amicable relationship,
Harvey being allowed to experiment on the royal herd
of deer and presenting interesting medical cases to
the king.

7.  Harvey lived during the European witch hunt. He was
involved in one of the cases, in 1634, and had to
examine four women accused of witchcraft. At a time
when belief in witches was commonplace and to deny
their existence was heresy, it would have been very
easy to interpret any suspicious behaviour or mark on
the body as positive evidence of witchcraft. It is much
to Harvey’s credit that he treated the case with an
open mind and was willing to consider scientific
explanations of the evidence allegedly showing
witchcraft. The alleged witches were found to be
innocent.


8.  In 1636 Harvey acted as doctor to a diplomatic mission sent to see the
Holy Roman emperor, Ferdinand II. This involved nearly a year of travel
around Europe. He met renowned German professor of medicine Casper
Hofmann at Nürnberg and attempted to demonstrate the circulation of
the blood to him. Harvey also had a wide interest
in philosophy, literature, and art. During the diplomatic mission of 1636
he visited Italy to look for paintings for the royal collection. He was
friends with Robert Fludd, an important English physician and
philosopher whose primary interest concerned natural magic,
and Thomas Hobbes, a famous political philosopher. He was also
acquainted with John Aubrey, the 17th-century biographer, who gave an
account of Harvey in his manuscript Brief Lives.
 Harvey was a committed royalist. He followed the king on the Scottish
campaigns of 1639, 1640, and 1641, was with him from 1642 to 1646
during the English Civil Wars, and was even present at the Battle of
Edgehill in 1642. His political views may be judged from the dedication
to the king in his most important book, De Motu Cordis (1628; see
below Discovery of circulation):


9.  In Harvey’s later life, he suffered from gout, kidney stones,
and insomnia. In 1651, following the publication of his final
work, Exercitationes de Generatione Animalium (Exercises on the
Generation of Animals), it is believed that Harvey attempted to
take his own life with laudanum (an alcoholic tincture of opium).
However, this attempt failed. On June 3, 1657, at the age of 79,
he died of a stroke.
 One of the worst setbacks Harvey experienced concerned the
loss of a great deal of written work when parliamentary troops
ransacked his house in Whitehall in 1642. He considered the loss
of his book on the generation of insects, which contained the
results of a great amount of research, to be the “greatest
crucifying” that he had in his life. He also lost notes on patients,
postmortem examinations, and animal dissections. Further
material was lost in the Great Fire of London in 1666, which
engulfed the library that Harvey helped establish at the Royal
College of Physicians.

10.  Harvey’s key work was Exercitatio Anatomica de Motu
Cordis et Sanguinis in Animalibus (Anatomical Exercise on
the Motion of the Heart and Blood in Animals), published
in 1628, with an English version in 1653. Harvey’s greatest
achievement was to recognize that the blood flows rapidly
around the human body, being pumped through a single
system of arteries and veins, and to support
this hypothesis with experiments and arguments. There
had been suggestions, both within the European tradition
(by 16th-century Spanish physician Servetus) and within
the Islamic tradition (by 13th-century Muslim
physician Ibn al-Nafīs) of a “lesser circulation,” whereby
blood circulated from the heart to the lungs and back,
without circulating around the whole body.

11.  Prior to Harvey, it was believed there were two separate
blood systems in the body. One carried purple, “nutritive”
blood and used the veins to distribute nutrition from
the liver to the rest of the body. The other carried scarlet,
“vivyfying” (or “vital”) blood and used the arteries to
distribute a life-giving principle from the lungs. Today
these blood systems are understood as deoxygenated
blood and oxygenated blood. However, at the time, the
influence of oxygen on blood was not understood.
Furthermore, blood was not thought to circulate around
the body—it was believed to be consumed by the body at
the same rate that it was produced. The capillaries, small
vessels linking the arteries and veins, were unknown at the
time, and their existence was not confirmed until later in
the 17th century, after Harvey, when the microscope had
been invented.

12.  Harvey claimed he was led to his discovery of the
circulation by consideration of the venous valves.
It was known that there were small flaps inside
the veins that allowed free passage of blood in
one direction but strongly inhibited the flow of
blood in the opposite direction. It was thought
that these flaps prevented pooling of the blood
under the influence of gravity, but Harvey was
able to show that all these flaps are
cardiocentrically oriented. For example, he
showed that in the jugular vein of the neck they
face downward, inhibiting blood flow away from
the heart, instead of upward, inhibiting pooling
due to gravity.

13.  Harvey’s main experiment concerned the amount of
blood flowing through the heart. He made estimates
of the volume of the ventricles, how efficient they
were in expelling blood, and the number of beats per
minute made by the heart. He was able to show, even
with conservative estimates, that more blood passed
through the heart than could possibly be accounted
for based on the then current understanding of blood
flow. Harvey’s values indicated the heart pumped
0.5–1 litre of blood per minute (modern values are
about 4 litres per minute at rest and 25 litres per
minute during exercise). The human body contains
about 5 litres of blood. The body simply could not
produce or consume that amount of blood so rapidly;
therefore, the blood had to circulate.

14.  It is also important that Harvey investigated the
nature of the heartbeat. Prior to Harvey, it was
thought that the active phase of the heartbeat,
when the muscles contract, was when the heart
increased its internal volume. So the active
motion of the heart was to draw blood into itself.
Harvey observed the heart beating in many
animals—particularly in cold-blooded animals
and in animals near death, because their
heartbeats were slow. He concluded that the
active phase of the heartbeat, when the muscles
contract, is when the heart decreases its internal
volume and that blood is expelled with
considerable force from the heart.

15.  It is tempting to view Harvey, with his quantitative experiment
and his model of the heart as a pump, as someone who
supported or was inspired by the new mathematical and
mechanical ideas of the 17th century, which played significant
roles in the scientific revolution of the time. However, there is a
need for considerable caution here. Harvey did quantify blood
flow, but his quantification is very approximate, and he
deliberately used underestimates to further his case. This is very
different from the precise quantification leading to the
mathematical laws of someone like Galileo. It was important that
Harvey saw the heart as a pump, but he saw it as an organic
pump, rather than as a mechanical pump. He also interpreted the
blood as having an irreducible life force of its own. Harvey was
deeply and bitterly opposed to the mechanical philosophy of
French mathematician and philosopher René Descartes as well as
to any purely mechanical conception of the human body.

16.  Harvey’s theory of circulation was opposed by
conservative physicians, but it was well established
by the time of his death. It is likely that Harvey
actually made his discovery of the circulation about
1618–19. Such a major shift in thinking about the
body needed to be very well supported by experiment
and argument to avoid immediate ridicule and
dismissal; hence the delay before the publication of
his central work. In 1649 Harvey
published Exercitationes Duae Anatomicae de
Circulatione Sanguinis, ad Joannem Riolanem, Filium,
Parisiensem (Two Anatomical Exercises on the
Circulation of the Blood) in response to criticism of
the circulation theory by French anatomist Jean
Riolan.